To enable high-throughput transmission and beamforming by a wireless communication station (e.g., an access point) that uses several transmit antennas, the channel should be fully excited to determine accurate beamforming coefficients. If channel reciprocity is assumed, a mobile station can fully excite the channel with at least as many antennas as the access point will use for transmissions to the mobile station. Fully exciting the channel in this manner may require more complex and expensive high-throughput mobile stations in which each transmit antenna is associated with one chain of radio-frequency (RF) circuitry. Exciting the channel with each transmit antenna may require the use of these several chains which consumes excess energy.
Thus, there are general needs for systems and methods that allow a mobile station to fully excite a channel to enable beamforming by an access point while reducing the complexity and/or cost of the mobile station. There are also general needs for systems and methods that allow a mobile station to fully excite a channel to enable beamforming by an access point while consuming less energy.